1. Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
2. Department of Applied Chemistry, Kobe City College of Technology, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2194, Japan
3. Faculty of Science, Kwansei Gakuin University, Uegahara, Nishinomiya 662-8501, Japan